Problem solved, touch wood, by full hard drive restore. Luckily, I had full image from about a month ago, so not too big a job.

I am using an i5 processor. 4MB RAM. Since installing latest Windows Update, OneNote doesn't appear on run. If I kill the inert OneNote process in task manager and run again, it then comes up with the clear cache dialogue. I choose open OneNote normally, it then opens. Choosing either of the other options (clear cache/delete settings) makes no difference to this behaviour. After closing OneNote, opening again returns to the inert process in task manager. I restored the system prior to the Windows Update, and the OneNote problem was solved. When Update subsequently reinstalled the OneNote problem returned. I have gone through this process several times. There seems little doubt about cause and effect here. The exact same symptoms are occuring with Firefox, although since that itself is an update, and not a MS app, I'm focusing on OneNote. Any help gratefully received.

Just discovered the same is also happening to iTunes. I realise that Firefox and iTunes have also been updated, but I have not reinstalled the Firefox update yet since the system restore. I will try uninstalling the iTunes update. It's starting to look like I'm going to have to disable windows update until this is fixed.

Hi, Have you tried to check what the result in Clean Boot mode is? Can you narrow down which update cause this issue? Alex Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Problem solved, touch wood, by full hard drive restore. Luckily, I had full image from about a month ago, so not too big a job.